One method of applying adhesive to the edge of a moving web is to simply spray adhesive onto the edge of the web. Any adhesive not received and retained by the web, namely the overspray, can contaminate equipment. Further, adhesive disposed at the distal edge of the web can string out and form angel hairs. Where the so-treated web is used in manufacturing an absorbent article such as a diaper, the angel hairs can have an uncomfortable tackiness for the body of the wearer of such an absorbent article. The strung out adhesive can also cause problems elsewhere in the manufacturing process.
Another method of applying adhesive simply sprays adhesive onto a moving web close to, but without quite reaching a lateral edge of the web. This method generally avoids adhesive going beyond the lateral edge, but also prevents applying adhesive at the distal edge, such that bonding of the distal edge of the web to another web or workpiece is frustrated.
Other methods of applying adhesive require complex registration systems. These registration systems can use printed, intermittent or oscillating, or other applicators to apply adhesive to a web.
Prior methods of applying chemicals to a web of material include utilizing a stencil between a chemical applicator and the web. In this manner, a defined surface area of the web of interest is covered by the chemicals. U.S. Pat. No. 5,415,717 to Pemeborn shows an example of a stencil belt controlling the placement of particles onto an underlying web. There is no disclosure of applying adhesives or applying the particles at the lateral edge of the underlying web.
U.S. Pat. Nos. 5,094,886 and 4,968,534 to Bogardy disclose methods and apparatus for impregnating the surface of a web with a liquid in the form of a pattern. Stencil pattern belt 211 is located between the web and the liquid applicator. This device would not work with hot melt adhesives because the adhesives would build up on the stencil belt and make the device inoperative over a short period of time. Further, there is no disclosure of applying adhesives at the lateral edge of the underlying web.
U.S. Pat. No. 5,501,149 to Schleinz et al disclose a dual substrate printing system. A printed substrate is located between an ink printing station and a backing substrate. The backing substrate receives ink that strikes through the printed substrate. Thus two ink patterns are formed. Column 4, lines 31-42 disclose registration of ink patterns. Registration is not needed or desired for the invention described herein. Further, there is no disclosure of applying adhesives in Schleinz et al, including not at the lateral edges of the printed substrate.
None of the art discloses having a second web in surface-to-surface relationship with a first web and extending outwardly from a lateral edge of the first web, and then applying adhesive at the lateral edge of the first web, some adhesive being received on the second web outwardly of the lateral edge of the first web.